Holiday that takes place on April 3rd of every year, or 3 days later if the holiday falls on a weekend. On this day, if an IT or similar worker in the high-technology industry has been good all year, the cheese weasel(not to be confused with the Wisconsin party band "The Cheese Weasels") will leave a piece of cheese(originally a slice of Kraft American, but has since become more commonplace to use any cheese) under the keyboard for said worker to find in the morning. Although the holiday's origin is murky, its tradition can be traced as far back as 1992 when a weasel was spotted carrying a Kraft Single. As Hallmark and The American Dairy Association are unaware of this holiday, it remains mostly non-commercial and is less well known than other mascot-visits-all-the-good-boys-and-girls holidays. Cheese weasel day also has its own song (which consequently has no known tune).

Official site is here: http://cheeseweaselday.com/

Fred: "Hey Bob, looks like you've been a good little IT guy this year."

Bob: "How you figure?"

Fred:***Points at Kraft Single under Bob's keyboard** "Why, you got visited by the cheese weasel of course! Don't you know its cheese weasel day?"

Bob: "Wow I completely forgot! I guess I have been good this year."
***Proceeds to eat the cheese**

Song:
“Who brings the cheese on April 3rd?
The Cheese Weasel
He’s not a silly bunny or a reindeer or a bird,
He’s the Cheese Weasel
He’s got a cute black tail
And tiny buck teeth
He doesn’t bring fish, and he
Doesn’t bring beef
So you’d better be good if you wanna get some cheese
From the Cheese Weasel.”